Affordance: The fundamental concept in engineering design

Abstract

In an effort to ground the art and practice of design, especially engineering design, in a formal science, there is a need to identify the core, fundamental concepts on which such a science should be based. Popular engineering design guides have long emphasized the importance of function as a fundamental concept. In this paper we argue that another concept, that of affordance, a term coined by the perceptual psychologist James J. Gibson to describe how animals perceive objects in their environment, is a more fundamental and in fact more powerful concept than function. Accepting affordance as a fundamental concept in design leads to a novel view of the design process, in which the designer's task is to find a system that possesses specific desired affordances, but does not possess other, undesired affordances. The concept of affordance also lends a unifying framework to a variety of disparate approaches to design, while suggesting new metrics and methods of decomposition to the design process in general.